Method and apparatus for controlling the flow of fluids

ABSTRACT

A method and apparatus controls the flow rate of a fluid that flows through a fluid path including a resiliently deformable portion. 
     A first roller has a cutout formed thereon on one side thereof, and a retainer is arranged in parallel with the first roller. The resiliently deformable portion of the fluid path is held between the first roller and the retainer. The first roller is rotatably supported by its rotary shaft. The first distance from the rotary shaft to the outer wall of the first roller on the side facing opposite the resiliently deformable portion may be varied in response to the variation in the angle that occurs when the first roller rotates about its rotary shaft. Thus, the second distance from the outer wall of the first roller on the side facing opposite the resiliently deformable portion to the retainer may be varied in response to the variation in the first distance, and the shape in cross section of the resiliently deformable portion may be varied according to the variation in the second distance. The flow rate of the fluid may be controlled by varying the shape in cross section of the resiliently deformable portion of the fluid path in this manner. The retainer may be replaced with a second roller having a configuration symmetrical with the first roller and being rotatably supported.

This is a divisional of Ser. No. 08/178,893, filed Jan. 7, 1994, U.S.Pat. No. 5,462,251 which is a divisional of Ser. No. 07/940,374, filedSep. 3, 1992, now U.S. Pat. No. 5,372,350 issued Dec. 13, 1994.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a flow rate controller, andmore particularly to a method of and an apparatus for controlling theflow rate of a fluid by compressing a resiliently deformable fluid pathportion or releasing it from the compression.

2. Description of the Prior Art

As shown in FIGS. 24(a) and (b), a typical flow rate controller that isknown to the relevant art, generally designated by 187, includes a fluidpath 182 inside which a resiliently deformable sleeve 183, or simply aresilient sleeve, is mounted. In this construction, the resilient sleeve183 has peripheral marginal edges 184 and 185 on the opposite sidesthereof rigidly fixed to the inner wall of the fluid path 182, with ahollow space 186 formed between the inner wall of the fluid path 182 andthe resilient sleeve 183. The flow rate of a fluid may be controlled byincreasing or decreasing the pressure to be applied to the hollow space186 to thereby vary the shape in cross section of the resilient sleeve183.

According to the flow rate controller as described above, the fluid path182 is completely closed by compressing the resilient sleeve 183 underthe pneumatic pressure applied thereto, as shown in FIGS. 24(c) and (d).This may disadvantageously cause fluid leaks or escapes through thecompressed fluid path. Particularly when the fluid flows under highpressures, more leaks or escapes may occur. Furthermore, when theresilient sleeve 183 is placed in its intermediate (half open) statebetween the fully opened state, and fully closed state when the fluidflows under high pressures (FIGS. 24(a) and (b)), the resilient sleeve183 may suffer small vibrations which cause the fluid to flowtherethrough at varying rates.

SUMMARY OF THE INVENTION

In one aspect of the present invention, the problems described above inconnection with the prior art are solved by providing a flow ratecontrol by using a combination of a cylindrical roller and a retainerthat are arranged to face opposite each other and hold a resilientlydeformable fluid path portion (or simply a resilient portion)therebetween, the roller having a cutout on one side which is formedsuch that the distance from its rotary shaft to the outer wall of theroller on the side facing opposite the fluid path varies every time theroller rotates through a particular angle. The flow rate may becontrolled by rotating the roller in this manner to press upon theresilient fluid path portion or to release it.

In another aspect of the present invention, those problems are alsosolved by providing a flow rate controller that includes a resilientfluid path and a combination of a cylindrical roller and retainerarranged to face opposite each other and hold a resiliently deformablefluid path portion (or simply a resilient portion) therebetween, theroller having a cutout on one side which is formed such that thedistance from its rotary shaft to the outer wall of the roller on theside facing opposite the fluid path varies every time the roller rotatesthrough a particular angle. The flow rate may be controlled by rotatingthe roller in this manner to press upon the resilient fluid path portionor to release it.

According to the method of the present invention, a first roller isprovided in parallel with a retainer for holding a resilient fluid pathtogether with the first roller. The first roller is rotated on itsrotary shaft, and the distance from the rotary shaft to the outer wallof the first roller on the side facing the resilient fluid path portionmay be varied every time the first roller rotates through a particularangle. The distance from the outer wall of the first roller on the sidefacing the resilient fluid path portion to the retainer on the sidefacing the opposite resilient fluid path portion may be variedaccordingly. The shape in cross section of the resilient fluid pathportion may be varied by varying this distance. The flow rate of thefluid that can flow through the resilient portion may be variedaccordingly. Alternatively, a common roller may be provided forconcurrently controlling the flow rates of the fluids that flow throughseveral fluid paths. The retainer may be formed symmetrically to thefirst roller so that it provides a symmetric surface, and may also beprovided to be rotatable.

According to the apparatus of the present invention, a casing isprovided for accepting the resilient portion of the fluid path. In thecasing, a first roller is provided in parallel with a retainer. Thefirst roller is rotatably supported, and holds the resilient fluid pathportion together with the retainer. The part of the first roller holdingthe resilient portion provides a control part, which is formed such thatthe distance from the rotary shaft of the first roller to the outer wallof the first roller on the side facing the resilient fluid path portionmay be varied according to every predetermined angle through which thefirst roller rotates about its rotary shaft. The part of the retainer onthe opposite side of the resilient fluid path portion facing the firstroller is provided in parallel with the rotary shaft of the firstroller. A single first roller may include several such control parts.

The retainer may be formed symmetrically to the first roller so that itprovides a symmetric surface, and also may be rotatably supported. Thefirst roller has a cylindrical form, and its control part includes acutout formed on one side of the cylinder. The outer wall of the firstroller on the side opposite the cutout is formed such that at least partof the outer wall of the first roller on the side opposite the cutoutcan engage the resilient fluid path portion when the first rollerrotates about its rotary shaft. Alternatively, the first roller has thecylindrical form, and may be mounted center to its rotary shaft off itsso that it can rotate eccentrically.

According to a variation of the apparatus, the first roller may includea peripheral guide track formed around its outer wall that alwaysengages the outer peripheral wall of the resilient fluid path portion,and is formed so that it can follow any variation in the shape in crosssection of the resilient fluid path portion that occurs when the firstroller rotates about its rotary shaft. The rotary shaft supporting thefirst roller may be coupled with means for moving the rotary shaft. Themeans for moving the rotary shaft may comprise the rack and pinionarrangement in which the rotary shaft is connected with the pinion whichengages the rack.

The peripheral guide track formed around the outer wall of the firstroller as described above may be provided on either or both of first andsecond rollers, and may be formed like a strip that is raised on thesurface or may be formed on the upper portion of the first roller thatis diameterically enlarged to provide a raised surface.

The retainer is a roller having the cylindrical form as described, butmay instead be provided by the wall surface of the casing in which thefirst roller is supported.

According to the method and apparatus of the invention as described sofar, the resilient portion of the fluid path may be controlled byholding it between the outer wall on the control part of the firstroller and the retainer in parallel with the first roller. There is norisk that the resilient portion held between the control part of a firstroller and retainer will vibrate even if the fluid flows at highvelocity through the resilient fluid path portion. Thus, the flow rateof the fluid can be controlled accurately. When the resilient portion isto be closed fully, the outer wall on the control part of the firstroller and the retainer can securely hold and press upon the resilientportion, and the resilient portion can be closed completely. Therefore,no fluid escape will occur and flow through the resilient portion evenwhen the fluid is under the high pressures.

The first roller includes the peripheral guide track formed around theouter wall of the control part on the first roller that always engagesthe outer peripheral surface of the resilient portion of the fluid pathand follows any variation in the shape in cross section of the resilientportion when the first roller rotates about its rotary shaft. Thisperipheral guide track ensures that the resilient portion can have theappropriate variations in shape in cross section when the shape in crosssection of the resilient portion is varied by rotating the first roller.The fully closing and fully opening sequence may be repeated. If thissequence is repeated by rotating first roller which does not have such aperipheral guide track, it is possible that there may be irregularitiesin the variation in the shape in cross section of the resilient portionevery time the sequence is repeated. The resilient portion may thengradually lose its resilience, and have to be replaced frequently.According to the present invention, the peripheral guide track on thefirst roller is provided for ensuring that the shape in cross section ofthe resilient portion can be varied appropriately in a predeterminedshape by following the guide track when the sequence is repeated. Thus,the resilient portion will be able to retain its resilience, so there isno need of replacing it frequently.

The first roller may have several control parts, and the flow rates forthe fluids through several fluid paths can be controlled by thecombination of the first roller having several control parts and theretainer. This: construction may provide multi-way valve functions. Itmay be apparent from the above description that the method and apparatusof the present invention may have a broad range of applications.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, features, and advantages of the presentinvention will become apparent from the detailed description of severalpreferred embodiments that will follow by reference to the accompanyingdrawings, in which:

FIGS. 1(a)-1(g) illustrate a roller in one preferred embodiment of thepresent invention, as well as the states in which the indexing motion ofthe roller occurs, in which FIG. 1(a) is a front view of the roller, andFIGS. 1(b) through (g) show respective sectional views of the rollertaken along the line A--A in FIG. 1(a) when the roller is differentstates after it has rotated successively through every specific angle inthe clockwise direction;

FIG. 2(a) is a longitudinal cross-sectional view of the rollerarrangement in FIGS. 2 and FIG. 2(b) is a sectional view of the rollerarrangement taken along the line B--B in FIG. 2(a);

FIGS. 3(a)-(c) are sectional views of the roller arrangement in FIGS. 2that have rotated through every specific angle, in which FIG. 3(a) showsthat the resilient fluid path portion opens fully, FIG. 3(b) shows thatthe resilient fluid path portion opens halfway, and FIG. 3(c) shows thatthe resilient fluid path portion closes fully;

FIGS. 4(a)-(c) shows a cross section of the rollers in the states shownin FIGS. 3, in which FIG. 4(a) is a sectional view taken along line C--Cin FIG. 3(a) , FIG. 4(b) is a sectional view taken along the line D--Din FIG. 3(b) , and FIG. 4(c) is a sectional view taken along the lineE--E it. FIG. 3(c) ;

FIG. 5 is a sectional view of a roller arrangement in anotherembodiment;

FIGS. 6(a)-(c) mounting of the rollers, in which FIG. 6(a) is aperspective view, FIG. 6(b) is a longitudinal section view, and FIG.6(c) is a transversal section view;

FIG. 7 is a sectional view of another embodiment including anintermediate film coating between the rollers and the resilient fluidpath;

FIGS. 8(a)-(d) show another variation of the rollers includingrespective peripheral guide tracks, in which FIG. 8(a) is a perspectiveview, and FIGS. 1(b) through (d) are longitudinal cross sections of therollers rotated through different specific angles;

FIGS. 9(a) through (d) are front views of variations of the rollerarrangement, each including peripheral guide tracks different than thoseshown in FIG. 8;

FIGS. 10(a)-(c) illustrate a roller in another preferred embodiment, inwhich FIG. 10(a) is a front view, FIG. 10(b) is a sectional view takenalong the line F--F in FIG. 11(a), and FIG. 11(c) is a longitudinalcross-section view of a roller arrangement in this embodiment;

FIG. 11 illustrates a roller in a further preferred embodiment, as wellas states in an indexing motion of the roller, in which FIG. 11(a) is afront view, and FIGS. 11(b) through (d) are sectional views: taken alongline G--G through the line K--K in FIG. 11(a) when the roller is in thedifferent states after it has rotated through every 120° angle;

FIGS. 12(a)-(c) illustrate a roller arrangement according to FIG. 12that provides a fluid filtering functions in which FIG. 12(a) shows afiltering process, FIG. 12(b) shows a backward cleaning process, andFIG. 12(c) shows a forward cleaning process;

FIGS. 13(a)-(c) shows the roller arrangement according to anotherpreferred embodiment, in which FIG. 13(a) is a perspective view, andFIGS. 13(b) and (c) illustrate a sectional view of this rollerarrangement in different states;

FIGS. 14(a)-(d) show a roller arrangement according to another preferredembodiment, in which FIG. 14(a) is a front view, and FIGS. 14(b) through(d) are sectional views taken along line N--N through line R--R showingstates of the roller as rotated through angles of 120°;

FIGS. 15(a)-(c) illustrate a roller arrangement according to FIG. 14that provides fluid filtering functions, in which FIG. 15(a) shows afiltering process, FIG. 15(b) shows a forward cleaning process, and FIG.15(c) shows a backward cleaning process; and

FIGS. 16(a) and (c) represent sectional views of a typical prior artroller arrangement, FIG. 16(b) corresponds to FIG. 16(a), showing alongitudinal section view, and FIG. 16(d) corresponds to FIG. 16(c),showing a longitudinal section view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1

Referring first to FIGS. 1 through 5, a first preferred embodiment ofthe present invention is described.

A roller assembly, generally designated by 5, includes a roller 1 havinga cylindrical form, and a central shaft 2 passing through the roller 1.The roller 1 has a cutout portion 3 formed centrally on one lateral sidethereof and an engaging portion 4 on the opposite lateral side. SeeFIGS. 1(a) and (b).

Similarly, another roller assembly, generally designated by 10, includesa roller 6 having a cylindrical form, and a central shaft 7 passingthrough the roller 6. The roller 6 has a cutout portion 8 formedcentrally on one lateral side thereof and an engaging portion 9 on theopposite lateral side. This is not shown in FIG. 1. Instead, it may beseen from FIG. 2. The roller assemblies 5 and 10 are symmetrical, andare operatively linked together.

A casing 15a houses the roller assemblies 5 and 10 whose respectiveshafts 2 and 7 are rotatably mounted to the casing 15a such that theroller assemblies are arranged in parallel and face opposite each otherwith a spacing therebetween. Each of the shafts 2 and 7 has a gear 11and 12 rigidly fixed to one end thereof respectively. Those gears 11 and12 mesh with each other. The shafts 2 and 7 are rotatably supported atboth ends by the casing 15a. For example, the shaft 2 has an extension2a on one side thereof, which projects out of the casing 15a. Thisextension 2a composes an operating part and may be coupled with anoperating handle (not shown). A fluid path 13 that has a hollowcylindrical form includes a resiliently deformable portion 14 (or simplya resilient portion ) which is inserted between the central cutoutportions 3 and 8 of the roller assemblies 5 and 10. The rollerassemblies 5 and 10 and the resilient portion 14 together form a fluidcontroller 15 (FIG. 2). When the roller 5 and/or 10 is referred tohereinafter, it should be understood to include the respective rollerassembly, unless othewise specified.

It may be seen from FIG. 1(b) that the roller 5 has a cross section asshown when it engages the resilient portion 14 of the fluid path 13. Inthe figure, the symbol "0" is the point of center in the central cutoutportion of the roller 5, about which the roller 5 rotates clockwise.When the roller 5 is in the state shown in FIG. 1(b), the distance fromthe center point "0" to the outer wall of the roller 5 on the sideengaging the resilient portion 14 of the fluid path 13 may berepresented by L1. FIG. 1(c) indicates the state of the roller 5 thathas rotated clockwise through an angle of 90°, beginning with the stateshown in FIG. 1(b). In the state shown in FIG. 1(c), the distance fromthe center point "0" to the outer wall of the roller 5 on the sideengaging the resilient portion 14 of the fluid path 13 may berepresented by L2. In the state shown in FIG. 1(d), the distance fromthe center point "0" to the outer wall of the roller 5 on the sideengaging the resilient portion 14 of the fluid path 13 may berepresented by L3. L3 is equal to the radius of the roller 5. When theroller 5 is rotated clockwise further until it reaches the state shownin FIG. 1(f), beginning with the state shown in FIG. 1(d), the distancefrom the center point "0" to the outer wall of the roller 5 on the sideengaging the resilient portion 14 of the fluid path 13 remainsunchanged, namely, "L3". Thus, when the roller 5 is between the states(d) and (f) in FIG. 1, the resilient portion 14 of the fluid path 13continues to be pressed upon most strongly by the roller 5. FIG. 1(e)and FIG. 1(g) indicate the states of the roller 5 that has rotatedclockwise through 180° and 270°, respectively, beginning with the statein FIG.

It may be seen from FIG. 1 that a part of the outer wall of the centralcutout portion 3 of the roller 5 always engages the resilient portion 14of the fluid path 13 while the roller 5 is rotating through every anglethat corresponds to every state shown in FIG. 1. Therefore, hen theroller 5 has completed one revolution, every part of the outer wall ofthe central cutout portion 3 of the roller 5 has engaged the resilientportion 14 at least one time. It is noted that the resilient portion 14of the fluid path 13 may have any size, e.g. a different diameter, andis not restricted to that shown in this embodiment. For example, theresilient portion 14 of the fluid path 13 may have a smaller diameter.In this case, there may be some parts of the outer wall of the centralcutout portion of the roller 5 that do not engage the resilient portion14 of the fluid path 13 when the roller 5 has rotated through onecomplete revolution. On the contrary, if the cutout portion is formedbigger than that shown in this embodiment, there may be some parts ofthe outer wall of the central cutout portion of the roller 5 that do notengage the resilient portion 14 of the fluid path 13 when the roller 5has rotated through one complete revolution in the before-mentionedcase.

As described, the side of the roller 5 opposite the cutout portion willbe referred to as the "engaging portion".

The angle of rotation of the roller 5 which is shown in FIG. 2(a), FIG.3(a) and FIG. 4(a) will be referred to as the reference angle relativeto all other possible angles. When the two rollers are at the referenceangle with the center points aligned as shown in FIG. 2(a), FIG. 3(a)and FIG. 4(a), the cutout portions 3 and 8 on the rollers 5 and 10 faceopposite each other so that the resilient portion 14 of the fluid path13 retains its original shape, that is, the round shape in cross section(fully opened state). When the rollers rotate through 180°, beginningwith the state of the reference angle, the resilient portion 14 will beheld between the engaging portions 4 and 9 of the rollers 5 and 10 sothat the opposite lateral sides 14a and 14b of the resilient portion 14facing the engaging portions 4 and 9 are pressed upon completely (fullyclosed state) as shown in FIG. 3(c) and FIG. 4(c). In this state, thefluid cannot flow through the resilient portion 14. The shapes of thecutout portions 2 and 8 and the gap between the two rollers 5 and 10 maybe determined by considering the design and size of the resilientportion. 14 of the fluid path 13 so that the resilient portion 14 can becontrolled to maintain the above states.

The part of the roller 5 that consists of the cutout portion 3 andengaging portion 4 provides a control part 16, and the part of theroller 10 that consists of the cutout portion 8 and engaging portion 9provides a control part 17.

The operation of the fluid flow controller 15 described above isdescribed below.

When the operating part 2a on the roller 5 is rotated, which usuallyoccurs by operating the handle (not shown) associated with the operatingpart 2a, the gear 11 on the roller 5 is rotated, causing the gear 12 inmesh with the gear 11 to rotate oppositely which causes the roller 10 torotate. Thus, the rollers 5 and 10 rotate at the same speed but in theopposite directions.

When the fluid path 13 is to be opened fully, the handle (not shown) isoperated to rotate the operating part 2a on the roller 5, which causesthe rollers 5 and 10 to rotate by means of the gears 11 and 12 so thatthe rollers 5, 10 are placed at the reference angle (FIG. 3(a) and FIG.4(a)).

Conversely, when the fluid path 13 is to be closed fully, the handle(not shown) is operated so that the operating part 2a on the roller,which causes the rollers 5, 10 to rotate by means of the gears 11 and 12so that so the rollers 5 and 10 are rotated through 180°, beginning withthe reference angle (FIG. 3(c) and FIG. 4(c)).

When the fluid path 13 is to be opened halfway, the handle (not shown)is operated until the operating part 2a on the roller 5 is rotated tothe intermediate state between the fully open state (reference angle)and the fully close state (180°). In this intermediate state, the shapein cross section of the resilient portion 14 is varied to allow thefluid to flow through the fluid path 13 at an appropriate rate. Then,the handle is stopped in its rest position. In this case, the resilientportion 14 of the fluid path 13 is firmly held between the engagingportions 4 and 9 of the rollers 5 and 10. Thus, there is no risk thatthe resilient portion 14 will vibrate even when the fluid flows at ahigh velocity.

This embodiment may be varied so that the engaging portion 4 on theroller 5 includes a smaller-diameter roller 18 as shown in FIG. 5. Inthis embodiment the engaging portion 9 on the roller 10 may include arecess 19 formed arcuately and having a diameter greater than the smallroller 18 by the thickness of the resilient portion 14, as shown in FIG.5. In this variation, when the fluid path 13 is to be closed fully, theresilient portion 14 may be held between the small roller 18 and therecess 19. This provides an improved sealing effect (see FIG. 5). Thisvariation may advantageously be used with fluid under high pressures.This variation may be varied further so that the engaging portions 4 and9 on both rollers 5 and 10 include smaller rollers, respectively. Thismay reduce the friction between the engaging portions 4 and 9 and theouter wall of the resilient portion 14, protecting the resilient portion14 against any possible wear caused by the friction. This is not shown.

In the embodiment described so far, the operating handle (not shown) isassociated with the operating part 2a of the roller 5, and the roller 5may be rotated by the operating handle. This mechanical link may bereplaced by the rack and pinion mechanism wherein pinions 112 and 113may be mounted to the upper end of the shaft 2 supporting the roller 5and to the upper end of the shaft 7 supporting the roller 10,respectively, and a rack 114 may be mounted between the pinions 112 and113, the rack 114 having teeth on opposite sides thereof engaging thecorresponding pinions 112 and 113 (FIG. 6(a), (b), (c)). The pinions 112and 113 may be mounted to the lower ends of the respective shafts 2 and7, but this is not shown. In alternative forms, the shaft supporting theoperating part 2a may be coupled with an automatic rotation controller,or the rack 114 may be coupled with an automatic motion controller. Ineither way, the rollers 5 and 10 may be rotated automatically. This isnot shown.

At least the area of each of the rollers 5 and 10 that engages theresilient portion 14 of the fluid path 13 may have a coating of Teflonor any other material that has a low friction coefficient.Alternatively, a thin film of Teflon or any other material that has alow coefficient may be provided on that area (not shown). It is alsopossible that a coating or film of Teflon or any other material that hasa low friction coefficient is provided on the area of the resilientportion 14 of the fluid path 13 on which engaging the rollers 5 and 10.Furthermore, as shown in FIG. 7, a sheet 116 of Teflon or any othermaterial that has a low friction coefficient may be provided between therollers 5 and 10 and the resilient portion 14 of the fluid path 13.

A variation of the embodiment described so far may be provided. In thisvariation, as shown in FIG. 8, peripheral guide tracks 117 and 118 and119 and 120 may he formed around the rollers 5 and 10 above and belowthe cutouts 3 and 8 and engaging portions 4 and 9 thereof, respectively.These guide tracks 117 and 118 and 119 and 120, are formed around theouter wall of respective rollers and always engage the outer peripheralwall of the resilient fluid path portion so that they can follow anyvariation in the shape in cross section of the resilient portion thatoccurs when the rollers rotate. FIG. 8(a) shows the guide tracksprovided on both rollers 5 and 10. The distance H between the guidetracks 117 and 118 is varied in accordance with the variation in theshape in cross section of the resilient portion such that it correspondsto a height H₁ when the fluid path is opened fully (FIG. 8(b)), a heightH₂ when the fluid path is opened halfway (FIG. 8(c)), a the height H₃when the fluid path is closed fully (FIG. 8(d)).

As may be understood from the above, those guide tracks can follow thevariations in the shape in cross section of the resilient portion 14that occur from the fully closed state to the fully opened state as therollers are rotating, and ensure that the resilient portion can have theappropriate variations in the shape in cross section when the shape incross section of the resilient portion is varied by rotating therollers.

As described, the guide tracks are formed around both rollers, but maybe provided on either of them, such as the guide tracks 117 and 118 onthe roller 5 as shown in FIG. 9(a). It is possible that only the guidetrack 117 is provided on the roller 5, and only the guide track 120 isprovided on the roller 10. It is also possible that the guide tracks 117and 118 are provided on the roller 5, and corresponding recesses 121 and122 that engage the guide tracks 117 and 118 are provided on the roller10 (FIG. 9(c)). The roller 5 may include the diametrically enlargedportions 123 and 124 on the upper and lower sides, which are formed toprovide the same configurations as the corresponding guide tracks 117and 118 shown in FIG. 8(a). Similarly, the roller 10 may also be formedto include the diametrically enlarged portions 125 and 126 (FIG. 9(d)).

EXAMPLE 2

Referring next to FIGS. 10 through 12, another preferred embodiment ofthe present invention is described.

In the preceding embodiment (EXAMPLE 1), one roller has one controlpart. In the embodiment shown in FIGS. 11 through 13, a roller assembly24 includes a roller 20 and a shaft 21 supporting the roller 20 whereintwo control parts 22 and 23 are provided. The control part 22 includes acutout 22a on one side, and an engaging portion 22b on the other side.Similarly, the control part 23 includes a cutout 23a on one side, and anengaging portion 23b on the other side. This may be seen from FIGS.10(a) and (b). A roller assembly 24a is similar to the roller assembly24, and has a symmetrical surface. These roller assemblies 24 and 24aare supported rotatably within a casing 49a, and hold two fluid paths25a and 25b therebetween. Thus, the flow rate controller 49 is providedas in the previous; embodiment (FIG. 10(c)).

The flow rate controller 49 may be used for controlling the flow ratesof the fluids through the corresponding fluid paths 25a and 25b in thesame manner as for the flow rate controller in the previous embodiment(EXAMPLE 1). As briefly described, when the roller assembly, or simplythe roller 24, is assumed to be at the angle of 0° as shown in FIG.10(c), the resilient portion of the fluid path 25a is held between thecutout 22a on the roller 24 and the corresponding cutout on the oppositeroller 24a. In this state, the resilient portion of the fluid path 25ais opened fully, as shown in FIG. 10(c). At the same time, the resilientportion of the fluid path 25b is held between the engaging portion 23bon the roller 24 and the corresponding engaging portion on the oppositeroller 24a, and the resilient portion of the fluid path 25b is closedfully as shown in FIG. 10(c). Then, when the roller 24 rotates through180° as shown in FIG. 10(a), the resilient portion of the fluid path 25ais held between the engaging portion 22b on the roller 24 and thecorresponding engaging portion on the opposite roller 24a, so theresilient portion of the fluid path 25a is closed fully. At the sametime, the resilient portion of the fluid path 25b is held between thecutout 23a on the roller 24 and the corresponding cutout on the oppositeroller 24a, so the resilient portion of the fluid path 25b is openedfully. In this way, the two control parts on the single roller 24 cancontrol the flow rates of the two fluids through the fluid paths 25a and25b.

The following example is the case where the roller has a number ofcontrol parts. Specifically, the flow rate controller includes a rollerthat has five control parts, and may be used as a fluid filteringapparatus as shown in FIG. 11. This roller arrangement is describedbelow with the aid of FIG. 11 and FIG. 12.

A first roller assembly, generally designated by 37, includes acylindrical roller 26 that has five control parts 27 through 31. Each ofthe control parts 27-31 has a respective one of cutouts 27a-31a on oneside thereof, and has a respective one of engaging portions 27b-31b.

A second roller assembly, not shown, is provided opposite the firstroller assembly 37 and has the identical and symmetrical rollerarrangement. Each of resilient portions 32 through 36 of a number offluid paths is held between the corresponding one of the control parts27-31 on the first roller 37 and the corresponding one of the controlparts on the second roller (not shown). The first and second rollerassemblies constitute the flow rate controller 38.

The flow rate controller 38 operates in the manner that it controls theflow rates of the fluids through the resilient portions 32-36 of thefluid path by rotating the first roller 37 and the second roller throughthe angles of 0° ("X" position), 120° ("Y" position) and 240° ("Z"position) to enable each of the control parts 27-31 to act upon eachcorresponding one of the resilient portions, thereby varying the shapein cross section of each corresponding one of the resilient portions sothe flow rates of the fluids through the resilient portions 32-36 can becontrolled. When the roller 37 is at the angle of 0° ("X" position), thestate for each of the control parts 27-31 is shown in cross section inFIG. 11(b). In the "X" position, the control parts 27 and 31 enable thecorresponding resilient portions 32 and 36 to be opened fully, throughwhich the respective fluids can flow, whereas the remaining controlparts 28, 29 and 30 enable the corresponding resilient portions 33, 34and 35 to be closed fully, through which the respective fluids cannotflow. Then, when the roller 37 rotates further through 120° ("Y"position), the state for each of the control parts 27-31 is shown incross section in FIG. 11(c). In the "Y" position, the control parts 28and 30 enable the corresponding resilient portions 33 and 35 to beopened fully, through which the respective fluids can flow, whereas theremaining control parts 27, 29 and 31 enable the corresponding resilientportions 32, 34 and 36 to be closed fully, through which the respectivefluids cannot flow. When the roller 37 rotates further through 120° (atotal of 240° ) ("Z" position), the state for each of the control parts27-31 is shown in cross section in FIG. 11(d). In the "Z" position, thecontrol parts 27 and 29 enable the corresponding resilient portions 32and 34 to be opened fully, through which the respective fluids can flow,whereas the remaining control parts 28, 30 and 31 enable thecorresponding resilient portions 33, 35 and 36 to be closed fully,through which the respective fluids cannot flow.

Each of the control parts 27-31 has a cutout that cooperates with therespective engaging portion for controlling the flow rate of the fluidthrough the respective resilient portion by opening or closing it fully,when the roller is at the angles of 0° ("X" position), 120° ("Y"position), and 240° ("Z" position).

In a flow rate controller 38, the roller 26 in the first roller assembly37 and the second roller in the first roller assembly 37 (not shown)which is symmetrical to the first roller 37 supported by respectivestationary shafts which are fixed in their respective positions eachtime the rollers rotates to the "X", "Y" and "Z" positions.

As shown in FIG. 12(a), a fluid filtering apparatus 41 may beconstructed by coupling a pump 39 and a filtering tank 40 with the flowrate controller 38 by means of a fluid path or conduit. In the schematicdiagram shown in FIG. 13, 42 designates a processed fluid outlet port,and 43 designates a liquid cleaner outlet port.

When the flow rate controller 38 is in a filtering process ("X"position) as shown in FIG. 12(a), a fluid to be filtered is deliveredfrom the pump 39 into the fluid rate controller 38 as indicated byarrows 44 and 45, from which the fluid is delivered to the filteringtank 40 as indicated by an arrow 46, and through which the fluid isfiltered as indicated by an arrow 47. The filtered fluid is then fedback to the flow rate controller 38 again as indicated by an arrow 48,from which it goes out through the processed fluid outlet port 42 asindicated by an arrow 49.

When the flow rate controller 38 is in a backward cleaning process ("Y"position) is shown in FIG. 12(b), the liquid cleaner is delivered fromthe pump 39 into the flow rate controller 38 as indicated by arrows 44and 50, from which the liquid cleaner is delivered to the filtering tank40 as indicated by arrows 51 and 52 where the interior of the thefiltering tank 40 is cleaned as indicated by an arrow 53. The liquidcleaner goes back into the flow rate controller 38 as indicated byarrows 54 and 55, from which it goes out through the outlet port 43 asindicated by an arrow 56.

When the flow rate controller 38 is in a forward cleaning process ("Z"position) as shown in FIG. 12(c), the liquid cleaner is delivered fromthe pump 39 into the flow rate controller 38 as indicated by arrows 44and 45, from which the liquid cleaner is delivered to the filtering tank40 as indicated by an arrow 46, and where the filtering tank 40 iscleaned as indicated by an arrow 47. The liquid cleaner goes back intothe flow rate controller 38 as indicated by arrows 48 and 57, from whichit goes out through the outlet port 43 as indicated by an arrow 58.

The above processes may be repeated for the fluid to be filtered next,upon completion of the forward cleaning process.

EXAMPLE 3

Referring next to FIGS. 13 through 15, another preferred embodiment ofthe present invention is described. In all of the preceding embodiments,the rollers are rotated about their respective stationary shafts.According to the current embodiment, the flow rate of the fluid can becontrolled by rotating the roller while its shaft is being moved.

The roller assembly in this embodiment is similar to that in theembodiment shown in FIG. 2, except that the shaft 2 for the roller 5providing the control part 16 and the shaft 7 for the roller 10providing the control part 17 have pinions 112 and 113 fixed to theirrespective upper ends, and a rack 114 is disposed between the twopinions 112 and 113, the rack 114 having teeth on the opposite sidesthat are in mesh with the corresponding pinions 112 and 113. Outside thepinion 112, a stationary rack 156 is provided in parallel with the rack114 and is fixed to the casing 15a. Similarly, outside the pinion 113, astationary rack 157 is provided in parallel with the rack 114, and isfixed to the casing 15a. Those racks 156 and 157 are in mesh with thecorresponding pinions 112 and 113. Parallel tracks 154 and 155 areprovided in the bottom across the casing 15a for accepting the bottomends of the corresponding shafts 2 and 7 for the rollers 5 and 10 sothat the shafts can travel along the respective tracks 154 and 157.

The resilient portion 159 of the fluid path 158 is held between therollers 5 and 10, which constitutes a flow rate controller 161 (FIG.13(i a), (b), (c)).

The operation of the flow rate controller 161 according to the currentembodiment is now described.

When each of the pinions 112 and 113 is placed on one side of 156a and157a of the respective stationary racks 156 and 157 as shown in FIG.13(b), the resilient portion 159 is located inside the cutouts 3 and 8on the rollers 5 and 10, so it is in its fully open state. Then, whenthe rack 114 is moved from the position shown in FIG. 13(b) in thedirection of an arrow 162, the rollers 5 and 10 are rolling until theyreach the position shown in FIG. 13(c) where the pinions 112 and 113 areplaced on a middle way 156b and 157b of the stationary racks 156 and157. In this position, the resilient portion 159 is pressed against bythe engaging portions 4 and 9, so it is in its fully closed state. Whenthe rollers 5 and 10 are placed between the positions shown in FIG.13(b) and FIG. 13(c), the resilient portion 159 is in its half openstate. The flow rate of the fluid can be controlled in this manner.

The stationary racks 156 and 157 may be replaced by tracks similar tothe tracks 154 and 156 that may be formed at the top across the casingfor supporting the shafts 2, 7. This is not shown.

The flow rate controller 161 according to the current embodiment may beapplied to a fluid filtering apparatus as described below.

As shown in FIG. 14, a cylindrical roller 163 has four control parts 164through 167. The control parts 164 through 167 include respectivecutouts 164a through 167a on one side thereof, and respective engagingportions 164b through 167b on the opposite side thereof.

Another cylindrical roller that is symmetrical to the above roller 163is provided (which is not shown), and resilient portions 169 through 172of a fluid path 168 corresponding to the control parts 164 through 167are held between the roller 163 and the other roller (not shown). Theroller assembly consisting of the rollers as described is mounted withina casing, which thus provides a flow rate controller 173.

The roller 163 and the other symmetrical roller (not shown) that holdsthe resilient portions 169 through 172 of the fluid path 168 togetherwith the roller 163 have a rack and pinion arrangement as described inconnection with the preceding embodiment shown in FIG. 21.

The flow rate controller 173 controls the flow rate of the fluid throughthe resilient portions 169 through 172 of the fluid path by causing theroller 163 and the other roller to rotate through 0° ("X" position),120° ("Y" position), and 240° ("Z" position), respectively, and byenabling each one of the control parts 164 through 167 to act upon eachcorresponding one of the resilient portions 169 through 172. When theroller 163 is at the angle of 0° ("X" position), each of the controlparts 164 through 167 has the shape in cross section as shown in FIG.14(b). In the "X" position, the control part 165 has no effect upon thecorresponding resilient portion 170 of the fluid path 168 (fully openstate), allowing the fluid to flow through the resilient portion 170,while the remaining control parts 164, 166, and 167 enable thecorresponding resilient portions 169, 171, and 172 to be closed fully,inhibiting the flow of the fluid through those resilient portions. Whenthe roller 163 rotates through 120° ("Y" position), each of the controlparts 164 through 167 has the shape in cross section as shown in FIG.14(c). In the "Y" position, the control part 164 has no effect upon thecorresponding resilient portion 169 of the fluid path 168 (fully openstate), allowing the flow of the fluid through the resilient portion169, while the remaining control parts 165, 166, and 167 enable thecorresponding resilient portions 170, 171, and 172 to be closed fully,inhibiting the flow of the fluid through those resilient portions. Whenthe roller 163 rotates further through 120° (a total of 240° ) ("Z"position), each of the control parts 164 through 167 has the shape incross section as shown in FIG. 14(d). In the "Z" position, the controlpart 167 has no effect upon the corresponding resilient portion 172 ofthe fluid path 168 (fully open state), allowing the flow of the fluidthrough the resilient portion 172, while the remaining control parts164, 165, and 166 enable the corresponding resilient portions 169, 170,and 171 to be closed fully, inhibiting the flow of the fluid throughthose resilient portions.

It may be appreciated that each of the control parts 164 through 167 ofthe roller 183 and another symmetrical roller also includes a cutoutthat acts upon the corresponding resilient portion of the fluid path toenable it to be opened fully or closed fully, when the roller rotatesthrough 0° ("X" position), 120° ("Y" position), and 240° ("Z" position).

The resilient portion 169 has an exit port 174, the resilient portion170 has a processed fluid outlet port 175, the resilient portion 171 hasan inlet port 177 through which a fluid to be processed and a liquidcleaner are delivered, a port 176 connected to one side (upper) of afiltering tank 180 and a port 179 connected to the other side (lower) ofthe filtering tank 180, and the resilient portion 172 has an exit port178. Those connections are shown in FIG. 15(a).

When the roller assembly 163 is in the "X" position as shown in FIG.15(a), it is in a fluid filtering process during which a fluid to beprocessed enters through the port 177, going through the resilientportions 172, 171 and then into the filtering tank 180 where the fluidis filtered via the upper side through the port 176, where the fluid isfiltered. The filtered fluid goes out from the filtering tank 180,entering the resilient portion 170 through the port 179 and then goingout through the port 175. These flows are indicated by the respectivearrows.

Then the roller assembly 163 is rolled from the "X" position (as shownin FIG. 15(a)) through 120° to the "Y" position as shown in FIG. 15(b).This position represents the cleaning process, during which, asindicated by the respective arrows in FIG. 15(b), the liquid cleanerenters through the port 177, going through the resilient portion 171 andthen through the port 176 into the filtering tank 180 via the upper sidefrom which the cleaner enters through the port 179 back into theresilient portion 169, the cleaner goes out through the port 174.

Finally, the roller assembly 163 is rolled from the "Y" position (asshown in FIG. 15(b)) through an additional 120° to the "Z" position asshown in FIG. 15(c). This position represents the backward cleaningprocess during which as indicated by the respective arrows in FIG.15(c), the cleaner enters through the port 177, going through theresilient portion 171 and then through the port 179 into the filteringtank 180 via the lower side where the backward cleaning occurs. Then thecleaner enters through the port 176 back into the resilient portion 172and then going out through the port 178.

The flow rate control may proceed as described above, and this proceduremay be repeated by operating the roller assembly as described above.

In the embodiment described in connection with FIG. 15, the rollerassembly 163 cooperates with its counterpart symmetrical roller assembly(not shown) to hold the resilient portions 169 through 172 therebetweenand thereby control their respective fluid flows. This embodiment may bemodified so that the roller assembly 163 may cooperate with the casingwall, rather than its couterpart roller assembly, to hold the resilientportions 169 through 172 and thereby control their respective fluidflows, although this is not shown. In this case, the casing wall thatengages the resilient portions may have a flat or curved surface. Theroller assembly 163 can roll along the appropriate configuration of thecasing wall.

Although the present invention has been described in connection with thepreferred embodiments thereof, it should be understood that variouschanges and modifications may be made without departing from the spiritand scope of the invention as defined in the appended claims.

What is claimed is:
 1. An apparatus for controlling the flow rate of afluid flowing through a fluid path at least partially defined by aresiliently deformable conduit portion, comprising:a casing having saidresiliently deformable conduit portion extending therethrough; a firstroller rotatably supported in said casing by a rotary shaft and aretainer in said casing, said first roller and said retainer having saidresiliently deformable conduit portion therebetween; and a controlsurface defined on said first roller for pressing said resilientlydeformable conduit portion toward said retainer to control fluid flowthrough said conduit portion, said control surface comprising a firstsurface portion that is curved as viewed in section, the section beingtaken perpendicular to said rotary shaft, and said first surface portionengaging and closing said resiliently deformable conduit portion in aclosed position of said first roller, and a second surface portion thatis curved as viewed in section, the section being taken perpendicular tosaid rotary shaft, said second surface portion being positioned alongone side of said resiliently deformable conduit portion in an openposition of said first roller; wherein said first roller has a guidetrack thereon defining the axial extent of said first and second surfaceportions of said control surface in the axial direction of said firstroller.
 2. The apparatus of claim 1, wherein said guide track has aposition on said first roller axially further away from the center ofsaid conduit portion at said second surface portion than at said firstsurface portion to allow for variation of the cross-sectional shape ofsaid conduit portion.
 3. The apparatus of claim 2, wherein said retainercomprises a second roller that is symmetrical with respect to said firstroller, said second roller being rotatably mounted in said casingparallel to said first roller.
 4. The apparatus of claim 2, wherein saidretainer comprises a second roller having an outer surface for engagingsaid guide track on said first roller.
 5. The apparatus of claim 4,wherein said outer surface of said second roller comprises a groove andsaid guide track comprises a flange received by said groove.
 6. Theapparatus of claim 4, wherein said outer surface of said second rollercomprises a second guide track symmetrical with respect to said guidetrack of said first roller.
 7. The apparatus of claim 1, wherein saidretainer comprises a second roller that is symmetrical with respect tosaid first roller, said second roller being rotatably mounted in saidcasing parallel to said first roller.
 8. The apparatus of claim 1,wherein said guide track comprises a flange.
 9. The apparatus of claim8, wherein said guide track comprises a pair of flanges spaced alongsaid first roller.
 10. An apparatus for controlling the flow rate of afluid, comprising:a fluid path comprising a resilient portion for havinga fluid flow there through, said resilient portion having an outerperipheral surface; a casing having said resilient portion of said fluidpath therein; a roller that is rotatably supported by a rotary shaft insaid casing and has an outer wall, and a retainer arranged in saidcasing, said roller and said retainer holding said resilient portiontherebetween; and a control means formed on said roller for acting uponsaid resilient portion together with said retainer, said control meanshaving a configuration such that a first distance from said rotary shaftto said outer wall of said roller on a side facing opposite saidresilient portion of said fluid path is variable in response tovariation of an angle through which said first roller rotates about saidrotary shaft; said retainer having a part facing opposite said controlmeans on said first roller and engaging said resilient portion of saidfluid path, said part being parallel with said rotary shaft of saidfirst roller; and said first roller further comprising a guide trackmeans formed around said outer wall for always engaging the outerperipheral surface of said resilient portion of said fluid path, saidguide track means following variations in cross sectional shape of saidresilient portion of said fluid path when said first roller rotatesabout said rotary shaft.
 11. The apparatus of claim 10, wherein saidcontrol means is a first control means and said roller further comprisesa second control means, spaced from said first control means on saidroller, for acting upon said resilient portion together with saidretainer, said second control means having a configuration such that asecond distance from said rotary shaft to said outer wall of said rolleron a side facing opposite said resilient portion of said fluid path isvariable in response to variation of an angle through which said firstroller rotates about said rotary shaft.